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The good news: I managed to fit a 3.62 E60 M5 diff into my 760Li. Got it from troyjeup. He mentioned doing it to his 745 on this forum years ago, but never followed up. I thought about using an Alpina diff, which is also 3.62, but it's just an open diff. I wanted LSD. Well, now I have it.

DO NOT DO THIS UPGRADE until I figure out what is going on. Right now, it's only an upgrade to LSD. It should be quicker, but it's not...yet.

It's a 3.62, compared to my 3.15 in the V12 car. But.... the TCU is a bit confused and won't shift quickly at redline. It revs to 6500 and hangs there for like, half a second and then shifts. Even Manual mode, Sport mode, you name it. Before mods, my car benchmarked using a Gtech Pro SS like this:

0-60 5.5 seconds
1/4 mile 13.5 seconds at 106 mph.

Now, because of the slower shifting, it's 2/10s slower 0-60 and the 1/4 mile. It should be a good bit quicker. Wheel spin is not the issue, I managed to get wheel spin even more under control than when I first benchmarked the car. In any case, I cannot beat my original times.

I am working with oetuning.com and whatever I can drum up to try to figure out a solution. Jeremy there has been very helpful and I would not hesitate to pay him to work on the car, if it comes to that.

I did a transmission adaptive learn reset in INPA--a few times. Even turned the car off and left it for an hour (Jeremy suggested at least 5 minutes) to ensure the car went to sleep and fully initialized the trans learning mode. Once it wakes up and goes through 10 miles or so, of really bumpy shifts, it re-learns and smooths out pretty well. But the car is measurably slower.

here's the logic I am pursuing to try to solve this: Use what BMW already has that works in a 7-series with an auto tranny, something that knows about the 3.62 differential. An Alpina B7 does.... so it's TCU and other trans-related parts must know what to do with the 3.62 M5 diff.

Here's what I am thinking: Hardware--- the TCU is probably different on the B7 (although I cannot confirm this using realoem). Where in realoem is the TCU?

Where can I get an Alpina B7 TCU profile (I am asking cn555ic the coderguy on the B3 forum). Can I just overlay that into my own TCU?

Here's what I CAN confirm with realoem, regarding the trans-related stuff and a B7, vs a E66 760Li

Trans cases are same family, 760 is: GA6HP26Z B7 is GA6HP26Z - UA.

But, they are different part numbers (But could be because they come
with a different Mechatronics internal part)

Yeah, thanks. I have actually seen that. I'm just not sure where they got their info, or how reliable it is. The actual specs came from "Richard Owen", who, if you click the link, it is a 404 file not found. I'd love to see this from a more reliable site, but I doubt BMW had a trans made with different ratios.

Yeah, thanks. I have actually seen that. I'm just not sure where they got their info, or how reliable it is. The actual specs came from "Richard Owen", who, if you click the link, it is a 404 file not found. I'd love to see this from a more reliable site, but I doubt BMW had a trans made with different ratios.

any chance it would be in an Alpina B7 manual that owners get in the techincal info section?

Finally got the used GTech Pro SS I bought to work with the PASS software. The graphing is very interesting. Also, the original 0-60 times the GTech told me for before and after are much better. It's a bit weird. You can see different values depending upon where you look on that thing.

I'll take what's in the graph.
0-60 of 5.073 with stock diff and 5.180 with M5 diff. But the M5 diff has a better 60' time.

Here's the main window of a 1/4 mile run, with the 760Li 3.15 diff (black line) and the M5 diff (red line). It shows that the M5 diff is faster at first, but the delay in shifting and the slow shifts overall, slow it's run down. What you SHOULD see is the red line pulling to the left on the graph, more and more, but the opposite occurs, since the ECU and/or TCU is freaking out.

Here's the first shift from first to second. You can clearly see the M5 diff is pulling ahead, and then, falls way back during the slower shift. Look at how the red line is actually ahead, then starts to slow and lag well before the shift. You can feel this.

The next shift from second to third. Since the M5 diff shifts at about 63mph the car is slowing down around 60 mph and thinking about the upcoming shift and then executing it slowly, making things worse for the 0-60 time.

Next shift from Third to fourth. According to my spreadsheets, the 760Li diff will not even shift until after 106 mph, so it does not get slowed down at all in a 1/4 mile run of 106 mph, but the laggy, slow shift of the car with the M5 diff at 97 mph, kills the run.

when I knew something was up with the ECU was: the first time I
drove it. I did not reset anything. I just went for a drive. The car
bumped pretty hard into each gear. The adaptive learn that the tranny
does was having to re-learn the new diff. I even got on the highway in
Sport mode and drove it up to 70mph and then got off the gas. The
trans BANGED into another gear and fricking chirped the tires!! in
like 4th gear. After a day it got way more smooth. No more banging and
chirping, but I could tell the trans was shifting slower, and I
measured it with the GTech and compared it to my stock runs.

So, I got out INPA and re-set the Auto tranny adaptive learn and it
did all that same crap all over again, and chirped on the highway, and
everything. I tried to measure it during the learn cycle and fricking
got "Transmission Fail Safe mode" on my dash and was driving around in
Second constantly, until I turned the car off and back on. Drove it
awhile, again, it got smoother, then slower shifting. So I reset it
AGAIN, same thing.

when I knew something was up with the ECU was: the first time I
drove it. I did not reset anything. I just went for a drive. The car
bumped pretty hard into each gear. The adaptive learn that the tranny
does was having to re-learn the new diff. I even got on the highway in
Sport mode and drove it up to 70mph and then got off the gas. The
trans BANGED into another gear and fricking chirped the tires!! in
like 4th gear. After a day it got way more smooth. No more banging and
chirping, but I could tell the trans was shifting slower, and I
measured it with the GTech and compared it to my stock runs.

So, I got out INPA and re-set the Auto tranny adaptive learn and it
did all that same crap all over again, and chirped on the highway, and
everything. I tried to measure it during the learn cycle and fricking
got "Transmission Fail Safe mode" on my dash and was driving around in
Second constantly, until I turned the car off and back on. Drove it
awhile, again, it got smoother, then slower shifting. So I reset it
AGAIN, same thing.

I'm thinking that there is some coding in some module that measures the output speed IE WHEEL SPEED and the engine speed during shifts and it's configured for the factory diff (Probably with ABS and VSC/DTC) and not for the M5 diff. You probably have to alter those coding parameters.

Thinking the same exact thing. buuuuttt.. Jeremy at oetuning warned me he has seen situations on German OBD2 auto tranny cars where the physical valving in the trans is not the same as well. That is why I am concerned about the mechatronic part number for an Alpina being a different part number than a 760, and the fact that Alpina part number is shared with no other car.

But... if it's only software, I agree with your assessment. I am working with someone offline to try to get the TCU bin for an Alpina. It's just a 7, with an AT, and a 3.62 diff, so it's as close as I can get to having compatibility. If anyone knows where I can get this, it sure would help. Might be in the Progman data files. I just am not sure how to read the header to see "Alpina" in them. I only see "E65", things like that.

I did try this with DSC off and got such immense wheelspin I turned DSC back on. I might just try a more leisurely launch with DSC off and see if I can get different results at the shift-points.

Have you tried putting it in manual shift so you can control the shift points and see if it responds as you would expect? Maybe ctsc can give you details on the mechatronics differences for Alpina as they sell all of those parts.

yeah, i tried manual mode. i mentioned it in the first few sentences. i know, theres a lot of info. i find manual mode is a joke. more like a mild suggestion to the transmission. it still does what it wants half the time. the shifts were very laggy.

i dont know what CTSC is. but thanks for the suggestion, ill try to look them up and check with them.

nope, not yet. I have the progman data files, and I've looked at a bunch of them (never used them and no expert at progman), but can't figure out where in the header it might say "Alpina B7". I am trying to get with someone to help me figure this out, later this week.

Yes, I have figured it all out, but this is all un-tested theory. Do all this hot-rodding at your own risk.

Bottom line, you need an 06 or later car, for the Alpina transmission (EGS) programming to work. The reason why: the EGS's .ODA file image is almost twice as big in bytes, starting in like mid 05 or so. You cannot flash the newer Alpina.ODA file onto an older EGS, because the bytes won't fit. Plus, it's all encoded, you'll never figure out where the final drive ratio value is--so you won't be editing it, and I have found NO one in the world who can or wants to program an EGS. I even begged OETuning.com, Jeremy, to do it and he said no. Has no experience diving in that deep. Dinan? I live in their town. They can do it. They won't touch it.

Also, I found out you can't simply"get" an EGS. It's built into the transmission. You have two choices:
1] get his Alpina transmission and use it (it has the EGS already in it), plus, of course, get his diff. You don't need his driveshaft, it's too short.
2] all the downloads of the BMW flash files have the Alpina .ODA in them, I could point you in the right direction, You could try to flash your own EGS in your transmission. It will likely work. The Z4 guys and others, do it all the time. But to make sure, just get his trans as well.

Update on my 2003 760Li with the M5 diff: it still downshifts a bit bumpy sometimes because the EGS is fighting the final drive ratio value, and it's slow to shift at redline at WOT, still. I got my ECU upgraded by OETuning and since the throttle sensitivity has been made more aggressive and the car is a bit faster, it's all even WORSE now. I re-set the trans adaptive learn mode and MAN oh MAN, it's been rough. Used to take me 15-20 miles for it to settle in. Now, 200 miles later, it's barely settling in. I tried to rush it one day and I went into failsafe mode. It's really important to get that final drive ratio value correct. I believe with the proper final drive ratio in the EGS none of this bumpy shifting would happen and shifts would be quicker at WOT. Very strange, my car shifts lightning quick at 6500 RPM at like 95% throttle, but super slow at WOT at 6500 RPM.

I plan to do some G-Tech 0-60 times and compare
1] stock
2] the M5 diff with stock ECU
3] and now, M5 diff with modded ECU.

I expect this: even quicker speed in each gear, but shifts are still too long, compared to stock. I will likely put the old diff back on, and then my car will be a stock drive ratio 760 with a modded ECU and should be pretty quick.

Food for thought: I have figured out some configurations which might work nice for an Alpina or M5 diff on another car. Your 2006-and-later 760Li is one. I am envious you get to try it. LMK how it goes.

The other would be a 645 or 650 with a 6-speed manual. It should not care about the final drive ratio value and you should be able to shift when and how you want. Plus, the V-8 6-speeds have a 2.93 final drive, not a 3.62. What a hoot!!!

Avoid an SMG, what a nightmare. Unless you know for a fact it's transmission programming lacks a final drive ratio value.

Only do an Automatic 6-series if you have a 650, not a 645, for the same EGS image/byte-size reasons I cite above. Then supercharge the 645 or 650 and you have basically the power of a N73 V12 in a 6-series, with the final drive of an M5. So, more torque than an M5, and the car weighs 800 lbs less than a 760Li.

It would also be fun to build an Alpina B7Li. Swap engine, trans, diff, etc. into your 750Li, and fly around in luxury. Why not?

Nice. I want to see if i can just swap the mechatronics because my tranny is about 8 months old and his is much older. maybe even buy a b7 mechatronic from CTSC and install it in my 760 since it has the same tranny. Is there any advantage of the m5 diff over the b7 diff or are they pretty much the same thing ?

Talk to Claus at CTSC and make sure that mechatronics swap includes the EGS and solves the issue. He should be fairly familiar with what I was talking about, since I emailed him over and over and he responded pretty nicely. He will tell you it will all blow up, but that's kinda his job. Don't worry about that part.

The M5 diff is a WHOLE nuther beast compared to the Alpina B7 diff. The B7 is an open diff like ours and totally plug and play. But you get the lame single tire-of-fire launches with DSC and DTC kicking in. The M6 is limited slip and required shortening my driveshaft by 6/10ths of an inch exactly (easy to cut and re-weld at a powertrain shop) . Plus, with an M5 diff you can NOT use our half-shafts, so I simply used M5 half shafts, which were 9mm shorter under full compression, but.. I tested the swing both up and down and there was no binding or disengagement in the M5 half shafts, so I am driving around with them in my car, thousands of miles later. The splines fit our hubs.

I had to shave off most of the aluminum side-cooling-fins on the M5 diff with a sawzall to get it to fit. Hits the cradle on the passenger side and the exhaust on the driver's side. I have a ton of pics. Just did not want anyone to try it until I figured out the final drive ratio problem. You might be the guinea pig.

You get all that M5--M6 stuff from Troy Jeup online.

do us a favor, please get a Gtech or something and do some baseline runs. Also, get with me if you want some tips on how to launch your car. It's not that easy and most of the time wants to start in 2nd gear.

The M5 diff is to big for my belt. I will stick with the b7 diff and I will find something to do a baseline run. I found that my car only starts in first in sport/ manual (duh) or if its not warmed up. I probably wont get to this for another 1 to 2 months but its going to happen as soon as I fix my Logic 7 and broken sway bar link Thanks for all the info you provided. I will definitely update with my progress as it progresses.

Ill just wait for those twin turbo 760's to come down in price there at 45,000$ right now. Add the b7 diff to that and well be good to go if its a swap that can be accomplished like the e66. but im too poor for that right now ill mod the e66 then the f02. the dreaded bearing issues the e60 m5's / m6's have is a major down side